1. Field of the Invention
The present invention relates to a method of cleaning probes fitted to a probe card for use in an electrical continuity test for a plurality of semiconductor integrated circuit devices formed on a semiconductor wafer, and so forth, and a cleaning system for use in carrying out the method.
2. Related Art
In the case of conducting an electrical continuity test for a plurality of semiconductor integrated circuit devices formed on a semiconductor wafer, a probe card provided with a plurality of probes fitted thereto is generally used.
When conducting the electrical continuity test, the probe card is used to cause the tip of the respective probes to come into contact with respective electrodes composed of aluminum, and the like, formed on the surface of the respective semiconductor integrated circuit devices.
Hereupon, as a thin oxide film is formed on the surface of the respective electrodes, the respective probes are set to be slidably in contact with the respective electrodes in order to remove the oxide film at the time of the contact with the respective electrodes. As a result, foreign particles composed of powders of metal such as aluminum, and the like, making up the electrodes, are caused to adhere to the surface of the respective probes.
Consequently, there has arisen a problem that electrical conductivity of the respective probes deteriorates due to the oxide film of the metal, adhered to the surface of the respective probes, and faulty contact between the respective electrodes and the respective probes results, making it impossible to conduct the electrical continuity test in a satisfactory manner. Accordingly, cleaning of the probe card has thus far been carried out in order to remove the foreign particles adhered to the surface of the respective probes.
Now, a conventional method of cleaning the probes is described hereinafter with reference to FIG. 5. In FIG. 5, reference numeral 110 denotes one of the probes making up the probe card, 111 the foreign particles, 120 an abrasive sheet, 121 abrasive grains contained inside the abrasive sheet 120, and 122 a sheet base material made of a silicone rubber.
In cleaning the probe 110 with the use of the abrasive sheet 120, there has been adopted a practice whereby the probe 110 is caused to pierce the abrasive sheet 120 several times, and the foreign particles 111 adhered to the probe 110 are scraped off by the agency of the abrasive grains 121 contained inside the abrasive sheet 120.
With such a method as described, however, a film of silicone rubber, a constituent material of the sheet base material 122, adheres to the probe 110, so that it has been necessary to apply an organic solvent to the probe 110 for removal of the film of silicone rubber, and further, to blow air thereto for drying the organic solvent.
Thus, with the conventional method of cleaning the probes, there are involved many steps of a cleaning process, such as scraping off of the foreign particles, application of the organic solvent, and the blowing of air, causing a problem that significant effort and time are required in carrying out these steps.
Further, since the organic solvent is used in the step of applying the organic solvent, a working environment has been anything but desirable to workers.
Furthermore, since the probe 110 is caused to pierce the abrasive sheet 120 to come into contact therewith, there has been a risk of the probe 110 undergoing deformation.
The present invention has been developed in view of such a circumstance as described in the foregoing, and it is therefore an object of the invention to provide a method of cleaning probes, capable of attaining reduction in the number of steps for a process of cleaning the probes, improvement in a cleaning environment, and less damage inflicted on the probes, and a cleaning device used for carrying out the method.
To this end, according to a first aspect of the invention, there is provided a method of cleaning a probe for removing foreign particles stuck to the probe, comprising the steps of: causing a standing wave comprising nodes and antinodes occurring in concentric circles to be generated inside a cylindrical body by subjecting the cylindrical body to ultrasonic vibration, and removing the foreign particles stuck to the surface of the probe by vibration of air occurring at the antinodes of the standing wave generated inside the cylindrical body by bringing the cylindrical body in close proximity to the probe.
Thus, since the foreign particles stuck to the surface of the probe are removed without contact by the effect of vibration of air occurring at the antinodes of the standing wave generated inside the cylindrical body by subjecting the cylindrical body to the ultrasonic vibration, it becomes possible to do away with troublesome work, which otherwise is required later on, such as removal of a film of silicone rubber by use of an organic solvent, work for drying the organic solvent by blowing air thereto, and so forth, thereby enabling simplification of work and shortening of work time as compared with a conventional case where the foreign particles are scraped off by causing the probe to pierce the abrasive sheet containing the abrasive grains. Further, since the organic solvent is unwanted, degradation in a working environment can be prevented. Furthermore, since the probe is cleaned by a non-contact method, cleaning can be carried out without causing problems such as deformation of the probe due to contact.
That is, excellent cleaning can be performed without inviting damage on the probe, and degradation in a working environment, which can otherwise occur at the time of cleaning, while reducing the number of steps for the process of cleaning the probe.
According to a second aspect of the invention, there is provided the method of cleaning the probe as set forth in the first aspect of the invention, wherein the cylindrical body is caused to undergo ultrasonic vibration at a plurality of varieties of resonance frequencies thereof.
That is, by causing the cylindrical body to undergo the ultrasonic vibration at the plurality of the varieties of resonance frequencies thereof, a plurality of varieties of standing waves are caused to be generated, and consequently, the number of nodes and antinodes of the standing waves generated inside the cylindrical body can be increased, thereby enabling cleaning of a plurality of the probes with ease.
As a result, a probe card comprising the plurality of the probes, for use in an electrical continuity test for a plurality of semiconductor integrated circuit devices, and so forth, can be cleaned with extreme ease and in short time.
That is, it becomes possible to significantly enhance a probability of the antinodes of the standing waves coinciding with a position of the respective probes so as to be able to cope with a tendency of a pitch among the probes becoming narrower accompanying narrowing down of a pitch among electrodes formed on the semiconductor integrated circuit devices, and a tendency of an increase in the number of the probes fitted to the probe card for application to a wafer in whole.
According to a third aspect of the invention, there is provided the method of cleaning the probe as in the first aspect or the second aspect of the invention, wherein the plurality of the probes are disposed so as to be arranged in line, and the cylindrical body is caused to make relative translation in the direction of a lineup of the probes as arranged.
More specifically, by causing the cylindrical body to make the relative translation in the direction of the lineup of the probes of the probe card provided with the plurality of the probes lined up, for use in conducting the electrical continuity test on the semiconductor integrated circuit devices, and the like, the foreign particles stuck to the respective probes can be removed smoothly and in short time by the agency of the standing waves generated inside the cylindrical body.
According to a fourth aspect of the invention, there is provided a cleaning system for cleaning probes so as to remove foreign particles stuck to the probes, comprising a cylindrical body, an ultrasonic vibrator installed in the cylindrical body, and an ultrasonic wave generation device for causing the ultrasonic vibrator to undergo ultrasonic vibration, wherein by causing the ultrasonic vibrator to undergo the ultrasonic vibration by the agency of the ultrasonic wave generation device, standing waves are caused to be generated in the cylindrical body, thereby removing the foreign particles stuck to the surface of the probes by the effect of vibration of air occurring at the anti nodes of the standing waves.
Thus, with the cleaning system for cleaning the probes as described above, the foreign particles stuck to the surface of the probes are removed without contact by the effect of vibration of air occurring at the antinodes of the standing waves generated inside the cylindrical body by subjecting the cylindrical body to the ultrasonic vibration, and consequently, it becomes possible to do away with the troublesome work, which otherwise is required later on, such as removal of the film of silicone rubber by use of the organic solvent, work for drying the organic solvent by blowing air thereto, and so forth, thereby enabling simplification of work and shortening of work time as compared with the conventional case where the foreign particles are scraped off by causing the probes to pierce the abrasive sheet containing the abrasive grains. Further, since the organic solvent is unwanted, degradation in a working environment can be prevented.
Furthermore, since the probes are cleaned through the non-contact method, cleaning can be carried out without causing problems such as deformation of the probes due to contact.
That is, excellent cleaning can be performed without inviting damage inflicted on the probes, and degradation in the working environment, which can otherwise occur at the time of cleaning, while reducing the number of steps for the process of cleaning the probes.
According to a fifth aspect of the invention, there is provided the cleaning system for cleaning the probes as in the fourth aspect of the invention, wherein the ultrasonic wave generation device comprises a plurality of ultrasonic wave generators for causing the ultrasonic vibrator to undergo ultrasonic vibration at the plurality of the varieties of resonance frequencies of the cylindrical body.
That is, by the agency of the plurality of the ultrasonic wave generators, the cylindrical body can be caused to undergo the ultrasonic vibration at the plurality of the varieties of resonance frequencies, and thereby a plurality of varieties of standing waves are caused to be generated inside the cylindrical body, increasing the number of nodes and antinodes of the standing waves, so that a plurality of the probes can be cleaned with ease.
Consequently, the probe card comprising the plurality of the probes, for use in the electrical continuity test for the plurality of the semiconductor integrated circuit devices, and so forth, can be cleaned with extreme ease and in short time.
That is, it becomes possible to significantly enhance a probability of the antinodes of the standing waves coinciding with a position of the respective probes so as to be able to cope with the tendency of the pitch among the probes becoming narrower accompanying narrowing down of the pitch among the electrodes formed on the semiconductor integrated circuit device, and the tendency of an increase in the number of the probes fitted to the probe card for application to a wafer in whole.
According to a sixth aspect of the invention, there is provided the cleaning system for cleaning the probes as in the fourth aspect of the fifth aspect of the invention, wherein the cylindrical body is formed in the shape of a cylinder closed at one end thereof with a bottom, is provided with the ultrasonic vibrator on the side of the bottom thereof, and is disposed such that an open side thereof is oriented toward the probes.
That is, by causing the ultrasonic vibrator installed on the bottom side of the cylindrical body to undergo the ultrasonic vibration by the agency of the ultrasonic wave generation device, the cylindrical body is caused to undergo the ultrasonic vibration with certainty, thereby enabling the standing waves to be generated inside the cylindrical body.
According to a seventh aspect of the invention, there is provided the cleaning system for cleaning the probes as in any of the fourth to sixth aspects of the invention, wherein a transfer means for causing the cylindrical body to relatively move in the direction of a lineup of the plurality of the probes arranged in line is provided.
That is, by causing the cylindrical body to make relative translation in the direction of the lineup of the probes, the plurality of the probes can be cleaned smoothly and in short time by the agency of the standing waves generated inside the cylindrical body.